Al-27 NMR spectra of the RECl3-AlCl3 (RE = Y, La) glasses and melts

Al-27 NMR spectra of pure crystalline and molten AlCl3 and of RECl3-AlCl3 ( RE = Y, La) glass forming binary mixtures have been obtained. Compositions corresponding mainly to YCl3/AlCl3 = 1/3 and LaCl3/AlCl3 = 1/3.7 have been studied from the glassy and crystalline state up to the melt. The Al-27 spe ctra can be unambiguously assigned to four-coordinated Al-species, such as Al2Cl6, `AlCl4', and `Al2Cl7'. The chemical shifts lie between 95 and 110 p pm, very well separated with the -1.6 ppm given by the `AlCl6' coordination in solid AlCl3. From the temperature evolution of the Al-27 NMR spectra, a description for the dynamic behaviour of these systems is proposed.